Repeat-while loop in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a repeat-while loop in Swift?

A repeat-while loop runs the code inside its block at least once, then keeps repeating as long as the condition is true. It's like doing something first, then checking if you should do it again.

beginner

How does a repeat-while loop differ from a while loop?

A repeat-while loop runs the code block first, then checks the condition. A while loop checks the condition first before running the code. So, repeat-while always runs at least once.

beginner

Write a simple Swift repeat-while loop that counts from 1 to 3.

var count = 1 repeat { print(count) count += 1 } while count <= 3 This prints 1, 2, and 3 each on a new line.

intermediate

Why might you choose a repeat-while loop over a while loop?

Use repeat-while when you want the code to run at least once no matter what, like asking a user for input and then checking if it’s valid.

beginner

What happens if the condition in a repeat-while loop is false right after the first run?

The loop stops after the first run because the condition is false. But the code inside still runs once before stopping.

What is guaranteed about the code inside a repeat-while loop?

A It runs at least once

B It might not run at all

C It runs only if the condition is true initially

D It runs twice before checking the condition

A repeat-while loop always runs the code inside once before checking the condition.

Which keyword starts a repeat-while loop in Swift?

A while

B do

C repeat

D loop

The repeat-while loop in Swift starts with the keyword 'repeat'.

When does the condition get checked in a repeat-while loop?

A Before the loop body runs

B After the loop body runs

C At the same time as the loop body runs

D Only once at the start

The condition is checked after the loop body runs in a repeat-while loop.

What will this code print? var x = 5 repeat { print(x) x -= 1 } while x > 3

A Nothing

B 5 only

C 5, 4, 3

D 5 and 4

It prints 5 first, then 4, then stops because x becomes 3 which is not > 3.

If the condition is false at the start, how many times does a repeat-while loop run?

A Once

B Zero times

C Twice

D Infinite times

The loop runs once before checking the condition, so it runs once even if the condition is false initially.

Explain how a repeat-while loop works and when you would use it.

Think about doing something first, then checking if you should do it again.

Write a Swift repeat-while loop that prints numbers from 1 to 5.

Start with a number 1, print it, add 1, and repeat while number is less or equal to 5.